/*
 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package com.sun.scenario.effect.compiler.model;

import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 */
public class SymbolTable {

    private final Map<String, Variable> globalVariableMap = new HashMap<String, Variable>();
    private final Map<String, Variable> localVariableMap = new HashMap<String, Variable>();
    private final Set<Function> globalFunctionSet = new HashSet<Function>();
    private int numSamplers;
    private int numParams;
    private boolean global = true;

    public SymbolTable() {
        declareCoreFunctions();
    }

    private Variable declareParamVariable(String name, Type type) {
        return declareVariable(name, type, null, null, -1, null, true);
    }

    public Variable declareVariable(String name, Type type,
                                    Qualifier qual)
    {
        return declareVariable(name, type, qual, null);
    }

    public Variable declareVariable(String name, Type type,
                                    Qualifier qual, Precision precision)
    {
        return declareVariable(name, type, qual, precision, -1, null, false);
    }

    public Variable declareVariable(String name, Type type,
                                    Qualifier qual, Precision precision,
                                    int arraySize, Object constValue)
    {
        return declareVariable(name, type, qual, precision,
                               arraySize, constValue, false);
    }

    public Variable declareVariable(String name, Type type,
                                    Qualifier qual, Precision precision,
                                    int arraySize, Object constValue,
                                    boolean isParam)
    {
        Map<String, Variable> vars = getVariablesForScope();
        Variable v = vars.get(name);
        if (v != null) {
            throw new RuntimeException("Variable '" + name + "' already declared");
        }

        if (arraySize == 0) {
            throw new RuntimeException("Array size cannot be zero");
        }

        int reg = -1;
        if (qual == Qualifier.PARAM) {
            if (!global) {
                throw new RuntimeException("Param variable can only be declared in global scope");
            }
            if (type.getBaseType() == BaseType.SAMPLER) {
                reg = numSamplers;
                numSamplers++;
            } else {
                reg = numParams;
                if (arraySize > 0) {
                    numParams += arraySize;
                } else {
                    numParams++;
                }
            }
        }

        v = new Variable(name, type, qual, precision,
                         reg, arraySize, constValue, isParam);
        vars.put(name, v);
        return v;
    }

    public Function declareFunction(String name, Type returnType, List<Param> params) {
        Function f = new Function(name, returnType, params);
        if (isFunctionDeclared(f)) {
            throw new RuntimeException("Function '" + name + "' already declared");
        }
        if (name.equals("main") && (params == null || params.isEmpty())) {
            if (localVariableMap.isEmpty()) {
                // core variables are implicitly declared for main() only
                for (Variable v : CoreSymbols.getAllVariables()) {
                    localVariableMap.put(v.getName(), v);
                }
            }
        }
        if (params != null) {
            // only declare parameters for non-core functions so that they
            // are visible in the function's scope (we skip this step for
            // core functions because the way the code is currently set up,
            // we'd end up declaring core function parameters in global scope;
            // we should clean this up later)
            for (Param param : params) {
                declareParamVariable(param.getName(), param.getType());
            }
        }
        declareUserFunction(f);
        return f;
    }

    public void enterFrame() {
        global = false;
        localVariableMap.clear();
    }

    public void exitFrame() {
        global = true;
    }

    private void declareCoreFunctions() {
        globalFunctionSet.addAll(CoreSymbols.getAllFunctions());
    }

    public Map<String, Variable> getGlobalVariables() {
        return globalVariableMap;
    }

    private boolean isFunctionDeclared(Function func) {
       return globalFunctionSet.contains(func);
    }

    private void declareUserFunction(Function func) {
        globalFunctionSet.add(func);
    }

    public Function getFunctionForSignature(String name, List<Type> ptypes) {
        return getFunctionForSignature(globalFunctionSet, name, ptypes);
    }

    static Function getFunctionForSignature(Set<Function> funcs,
                                            String name,
                                            List<Type> ptypes)
    {
        for (Function f : funcs) {
            List<Param> params = f.getParams();
            if (name.equals(f.getName()) && params.size() == ptypes.size()) {
                boolean match = true;
                for (int i = 0; i < params.size(); i++) {
                    if (params.get(i).getType() != ptypes.get(i)) {
                        match = false;
                        break;
                    }
                }
                if (match) {
                    return f;
                }
            }
        }
        return null;
    }

    public Map<String, Variable> getVariablesForScope() {
        if (global) {
            return globalVariableMap;
        } else {
            return localVariableMap;
        }
    }

    public int getNumSamplers() {
        return numSamplers;
    }
}